System and method for occupancy sensing with enhanced functionality

ABSTRACT

A system and method provide fail-safe operation of a lighting system. A lighting level detector is used to obtain a baseline lighting level for a low-intensity light. If the detector measures less than the baseline level when an occupancy sensor determines the space is unoccupied, a high-intensity light is energized and an indication is provided to a user that the low-intensity light has failed. A method provides daylighting operation of a lighting system. An occupancy sensor can have Wi-Fi functionality to enable remote configuration of the sensor. A line voltage occupancy sensor can include an interface with low voltage devices. An occupancy sensor can include an integral interface to enable an external control system to override the sensor&#39;s normal logic under emergency conditions. An occupancy sensor can include an active temperature compensation feature. An occupancy sensor can also incorporate an automatically adjustable coverage area.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional patent application of pending U.S. patentapplication Ser. No. 13/775,534, filed Feb. 25, 2013, titled “System andMethod for Occupancy Sensing with Enhanced Functionality,” the entiretyof which application is incorporated herein.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to occupancy sensing systems,and more particularly to an improved system and method for occupancysensing systems having enhanced functionality.

BACKGROUND OF THE DISCLOSURE

Occupancy sensors are designed to save energy by detecting the presenceof a moving object in an area of coverage and switching a light sourceon and off depending upon the presence of the moving object. Forexample, when motion is detected within the area of coverage, the lightsource is turned on. Alternatively, when motion is not detectedindicating that the area of coverage is not occupied, the light sourceis turned off after a predetermined period of time. Occupancy sensorsthus facilitate electrical energy savings by automating the functions ofa light switch or an electrical outlet.

Occupancy sensors can be used to monitor any of a variety of locations,including office spaces, hotel rooms, stairwells, and the like. Whereoccupancy sensors are used to control lighting in spaces such asstairwells or other areas where visibility is important, occupancysensor failure can present a safety hazard because lighting may remainoff even when a person has entered the area. To address such potentialsafety hazards, the National Fire Protection Association (NFPA) 101 LifeSafety Code requires that low level ambient lighting be provided instairwells and other areas where visibility is important even when theyare not occupied. Thus, one high-intensity light may provide normalspace illumination when motion is detected, while a second,low-intensity, light may provide the low level ambient lighting whenmotion is not detected. Such arrangements provide energy savings, alongwith desired safety, because the high-intensity light is illuminatedonly when the space is occupied, while the low-intensity light providesdesired safety illumination levels when the space is not occupied.

A disadvantage of using a high-intensity light and a low-intensity lightconfiguration is the potential for the low-intensity ambient lightfailing, and subsequently the occupancy sensor malfunctioning so thatthe high-intensity light does not turn on when the space is occupied.Furthermore, a high-intensity light and a low-intensity lightconfiguration does not provide a way to determine if the low-intensitylight has failed other than if a person enters the space and visuallydetermines that both the high-intensity light and the low-intensitylight have not turned on. Thus, as will be appreciated, a high-intensitylight and a low-intensity configuration would provide a “safe”configuration only if the low-intensity light is functioning properly.

It would, therefore, be desirable to provide a fail-safe arrangement foran occupancy sensor that ensures that a space is illuminated even in theevent that the low-intensity light fails. It would also be desirable toprovide an arrangement in which failed low-intensity lighting can beautomatically identified so that repair can be scheduled in an efficientmanner.

It would further be desirable to provide an occupancy sensor having avariety of advanced functionality. For example, current occupancysensors include configuration features that can only be accessed by auser having direct physical access to the sensor. For sensors positionedin elevated locations this is inconvenient and can pose a safety hazardas it requires the user to be on a ladder. It would therefore bedesirable to provide an occupancy sensor that is remotely configurableso that a user standing on the ground can remotely configure one or moreoccupancy sensors positioned on a ceiling, high wall, or the like.

In addition, current applications that employ multiple occupancy sensors(e.g., large halls, multiple entrance rooms, or stairways), do so usinga plurality of low voltage occupancy sensors. Low voltage occupancysensors are sensors without a relay, and as such they cannot directlycontrol a connected load. Rather, they must be connected to a separateload control device such as a power pack, which switches the load on/offin response to a signal from the occupancy sensors. It would bedesirable to provide a line voltage occupancy sensor with a built-inload control feature as well as interfaces to a plurality of low voltageoccupancy sensors so that the line voltage sensor can act as a loadcontrol device for the low voltage sensors.

Moreover, current occupancy sensors are often coupled to buildingautomation systems or building management systems (BMS). Under emergencyconditions (e.g., fire), the BMS acts to override the normal operationof the occupancy sensors to ensure that the lights stay on to aidemergency personnel, such as firemen as well as security personnel.Coupling of the occupancy sensors to the BMS is often accomplishedthrough external interface units. As will be appreciated, providingseparate external interface units can result in increased system cost.It would be desirable, therefore, to provide an occupancy sensor with anintegral interface for connecting to a BMS to enable the BMS to overridethe normal operation of the sensor under emergency conditions.

In addition, passive infrared (PIR) occupancy sensors operate by sensinga body having a heat signature in excess of background infrared (IR)levels. As the ambient temperature of a monitored space rises, thedifference between human body temperature and the ambient temperaturedecreases, and as a result PIR occupancy sensors can be less able todifferentiate the heat of a human body from the heat of thesurroundings. This may be particularly acute where the occupancy sensoris deployed in a hot climate where the temperature of the monitoredspace can be very high if air conditioning is not in use. It would bedesirable to provide an occupancy sensor with an active temperaturecompensation feature to ensure that passive infrared (PIR) sensorsappropriately indicate an occupancy condition even at high ambienttemperatures. In addition, it would be desirable to provide an occupancysensor with an automatically adjustable coverage area, so as toeliminate the need for masking inserts.

SUMMARY OF THE DISCLOSURE

A load control system is disclosed, comprising an occupancy sensor forsensing an occupancy condition of a monitored area. The load controlsystem may also include a light sensor for providing a lighting signalrepresentative of a lighting level of the monitored area. Regardless ofthe occupancy condition of the monitored area, an associated load may beenergized when the lighting signal indicates the lighting level is belowa predetermined threshold lighting level.

A method is disclosed for controlling an electrical load. The method mayinclude receiving, at a load control device, a lighting signalrepresentative of a lighting level of a monitored area; and energizingan electrical load when the lighting signal indicates the lighting levelis below a predetermined threshold lighting level and an occupancysensor associated with the monitored area indicates the monitored areais vacant.

A method is disclosed for controlling an electrical load. The method mayinclude, at a light sensor, detecting an ambient light level in amonitored space, and, when the controlled electrical load is notenergized, controlling the electrical load in response to an amount oflight in the space as measured by the light sensor.

The method may further comprise, at an occupancy sensor, detecting anoccupancy condition of the monitored space, and controlling theelectrical load in response to the as-measured amount of light in thespace and the occupancy condition of the monitored space. The method mayalso include controlling the electrical load to be in a dimmed orde-energized state when the measured amount of light in the spaceexceeds a predetermined level. In some embodiments, controlling theelectrical load to be in a dimmed or de-energized state may occurregardless of the occupancy condition of the monitored space.

The light sensor and the occupancy sensor may be integrated in a singlehousing coupled to a processor. Alternatively, the light sensor and theoccupancy sensor may be provided in separate housings. The method mayfurther include compensating for an amount of light contributed by theelectrical load in determining the amount of light in the space asmeasured by the light sensor. In some embodiments, compensating maycomprise performing a calibration when a manual set point of the lightsensor is being programmed. In other embodiments, calibration mayinclude switching the electrical load on and off a plurality of times tomeasure an amount of light level change that occurs. The method mayfurther include adjusting a hysteresis value to be an amount greaterthan the light level change. In some embodiments the hysteresis valuemay be twice the amount of the light level change. In other embodiments,the hysteresis value may be stored non-volatile memory.

An occupancy sensor is disclosed, comprising an occupancy sensingelement, and a wireless transceiver for receiving wireless signals froma remote device to configure the occupancy sensor from a remotelocation. The wireless transceiver may be further configured to transmitwireless signals to the remote device, where the transmitted wirelesssignals including information representative of an operationalcharacteristic of the wireless occupancy sensor during a previous timeperiod.

A method is disclosed for controlling a load with a wireless occupancysensor. The method may include receiving, at a wireless occupancysensor, wireless signals from a remote device, where the wirelesssignals configure the occupancy sensor. The method may further includetransmitting, from the wireless occupancy sensor, wireless signals tothe remote device. The transmitted wireless signals may includeinformation representative of an operational characteristic of saidwireless occupancy sensor during a previous time period.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example, a specific embodiment of the disclosed device willnow be described, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of an embodiment of the disclosed system;

FIG. 2 is a schematic diagram of an exemplary occupancy sensing systemaccording to an embodiment of the disclosure;

FIG. 3 is a schematic diagram of an exemplary occupancy sensing systemaccording to a further embodiment;

FIG. 4 is a schematic diagram of an occupancy sensing system accordingto a further embodiment;

FIG. 5 is a schematic diagram of an embodiment of the disclosed systemof FIG. 4;

FIGS. 6A-6D are a series of screen shots from an exemplary remote deviceillustrating steps for configuring a wireless occupancy sensor accordingto a further embodiment;

FIG. 7 is a schematic diagram of an occupancy sensing system accordingto a further embodiment;

FIGS. 8A-8D are a series of screen shots from an exemplary smart phoneillustrating steps for provisioning a device in a Wi-Fi network.

FIG. 9 is a schematic showing a line voltage sensor according to anembodiment of the disclosure;

FIG. 10 is a block diagram illustrating the line voltage sensor of FIG.9;

FIG. 11 is a schematic showing a line voltage sensor according to afurther embodiment;

FIG. 12 is a schematic of an occupancy sensor according to a furtherembodiment;

FIG. 13 is a schematic of an occupancy sensor according to a furtherembodiment;

FIG. 14 is a schematic of an occupancy sensor according to a furtherembodiment;

FIG. 15 is a logic diagram illustrating an exemplary embodiment of thedisclosed method;

FIG. 16 is a logic diagram illustrating another exemplary embodiment ofthe disclosed method; and

FIG. 17 is a logic diagram illustrating a further exemplary embodimentof the disclosed method.

DETAILED DESCRIPTION

A system and method are disclosed for providing fail-safe operation of alighting system so that primary lighting associated with an occupancysensor will be energized in the event that a low level ambient “safety”light malfunctions. As will be appreciated, this functionality may bedesirable for applications in which lighting systems may impact publicsafety. Examples of such applications may include, but are not limitedto, lighting in public staircases, parking lots, parking ramps, or otherareas where public safety may be compromised if a low level ambient“safety” lighting fails to energize, etc. The disclosed system andmethod may find application with a variety of different types ofoccupancy sensing technologies, load control devices, and loads.

Certain governmental life safety organizations have standards thatrequire low level ambient lighting in stairwells and/or other publicareas even when the stairwells are not occupied. For example, theNational Fire Protection Association (NFPA) 101 Life Safety Coderequires low level ambient lighting (e.g., 1 foot-candle (fc) ofillumination) to be provided in stairwells even when the stairwells arenot occupied. This compares to the at least 10 fc of illuminationrequired by NFPA 101, the Life Safety Code, when stairways are occupied(see NFPA 101, Section 7.8.1.3) Thus, as shown in FIG. 1, a space 1,such as but not limited to a stairwell, preferably includes twodifferent types of lighting loads. The first light 2 may be ahigh-intensity light configured to provide a level of lighting normallyassociated with an occupied space. The second light 4 may be arelatively low-intensity “safety” light configured to provide a minimalamount of light required to enable a person to safely navigate the space1 should the first light 2 fail, or should an associated occupancysensor fail to signal the first light 2 to energize.

It is generally desirable to turn off the first light 2 when the space 1is unoccupied in order to conserve energy. As such, the second light 4is used as a safety precaution to provide a small amount of light whenthe space is vacant in the event that the occupancy system fails to turnon the first light 2 after a person enters the space. If, however, thesecond light 4 fails (e.g., burns out), this safety feature is defeated.The failure of the second light 4 may go undiscovered because, bydesign, the second light 4 may be configured to turn on only when thespace is vacant. The disclosed system is configured to automaticallydetect a failure in the second light 4 so that the first light 2 can beimmediately energized, regardless of whether the space 1 is occupied.Thus, the space 1 will never be completely dark. In one embodiment, theoccupancy sensor 6 is configured to sense failure of the second light 4.The occupancy sensor 6 may transmit a signal to the first light 2 toenergize regardless of occupancy in the space 1 in order to maintainsafe conditions in the space.

Although the illustrated embodiment shows that the space 1 is servicedby one first light 2 and one second light 4, it will be appreciated bythose of ordinary skill in the art that additional first and/or secondlights may be provided. In addition, multiple occupancy sensors 6 canalso be provided to sense occupancy in the space 1.

In one embodiment, the occupancy sensor 6 automatically detects when thesecond light 4 has failed, and in turn transmits a signal to the firstlight 2 to energize even when the space 1 is vacant. In addition, upondetecting that the second light 4 has failed, the occupancy sensor 6 maytransmit an alarm signal to alert operational personnel (e.g., buildingmanagement) of the failure so that corrective actions can be taken in atimely manner.

FIG. 2 shows an embodiment of the occupancy sensor 6 coupled to a loadcontrol device 8 and a load 10. The occupancy sensor 6 may include aprocessor 12 configured to control one or more operational aspects ofthe occupancy sensor. The processor 12 may also be configured to controland decode communication signals sent between the occupancy sensor 6 andthe load control device 8 via signal line 18. The memory 14 may beassociated with the processor 12 for storing operational andconfiguration information relating to the occupancy sensor 6 and/orother elements of the system. The memory 14 may be any of a variety ofvolatile or non-volatile memory devices now or hereinafter known bythose of ordinary skill in the art.

The occupancy sensor 6 may receive power from the load control device 8via the power line 16, and may transmit signals (e.g., occupancysignals) to the load control device 8 via signal line 18. In response tosignals received from the occupancy sensor 6, the load control device 8may energize the load 10 via one or more power lines 20. In oneembodiment, the load 10 may include at least one light. The load controldevice 8 may receive line power from a building power source 22.Alternatively, the load control device 8 may be powered by an internalbattery (not shown).

When the load control device 8 receives an occupancy signal from theoccupancy sensor 6, it may control operation of the associated load 10accordingly. For example, when the occupancy signal 6 transmits a signalto the load control device 8 communicating that the space is occupied,the load control device 8 may energize the load 10 by providing powervia the power line 20.

Although the illustrated embodiments include a single occupancy sensor6, a single load control device 8, and a single load 10, it will beappreciated by those of ordinary skill in the art that any number ofsensors, loads and/or load control devices may be used in combination toprovide an occupancy sensing system having a desired functionality andcoverage. For example, it will be appreciated that a space, such as butnot limited to a public parking garage, may have multiple stairwellsthat may be monitored by multiple occupancy sensors. In addition, one ormore loads may be associated with each occupancy sensor. Alternatively,one or more occupancy sensors may be associated with each load. Furthercombinations of components are contemplated, as will be appreciated byone of ordinary skill in the art.

In addition, although the occupancy sensor 6 and the load control device8 are illustrated as being separate components, in some embodiments theoccupancy sensor 6 may include internal load control functionality,eliminating the need for a separate load control device 8.

The occupancy sensor 6 may be in communication with an ambient lightdetector 24, such as but not limited to, a photocell. Although theambient light detector 24 is shown as being external to the occupancysensor 6, it may also be an integral part of the sensor 6. The ambientlight detector 24 may be operable to sense an ambient lighting level inthe monitored space and to provide associated light level information tothe processor 12. Based on the ambient lighting level informationprovided by the ambient light detector 24, the processor 12 may adjustor override the normal logic of the occupancy sensor 6. In someembodiments the photocell can have its own controller that cancommunicate with the occupancy sensor and/or the load control device.

In one embodiment, ambient lighting levels are stored in the memory 14,and the processor 12 compares the light level information provided bythe ambient light detector 24 to determine if the measured ambient lightlevel in the monitored space is at or above a predetermined level. Ifthe measured ambient light level is equal to or exceeds thepredetermined level, then it may be assumed that the second light 4 (seeFIG. 1) is functional, and the normal logic of the occupancy sensor 6may prevail (i.e., the first light 2 is turned on if an occupancycondition is sensed, and the first light 2 is allowed to turn off aftera predetermined delay period of no occupancy). If, however, the measuredambient light level is below the predetermined level, it may be assumedthat the second light 4 has failed, and the normal logic of theoccupancy sensor 6 may be overridden so that the first light 2 isautomatically and immediately energized to provide a safe lightingcondition in the monitored space. In this condition, the first light 2may remain energized regardless of whether the occupancy sensor 6determines that the space is occupied. In addition, normal timeouts forthe first light 4 may be overridden so that a constant ON conditionexists for the first light 2.

In some embodiments the system can be calibrated to “teach” theprocessor how much light should be expected when only the second light 4is on for a particular installation. Such calibration can be performedin a manual or automatic fashion.

In some embodiments, the occupancy sensor processor 12 may be connectedto a building automation system or building management system (BMS) 26via a hard wired or wireless communication link 28. The processor 12 maytransmit a signal to the BMS 26 if the measured ambient light level isdetermined to be below the predetermined level. This, in turn, maysignal an alarm that alerts building management personnel that thesecond light 4 associated with the monitored space has failed, and thatcorrective action is necessary. In one embodiment, the processor 12sends a periodic signal to the BMS 26 until the occupancy sensor 6 isreset, either via a manual reset at the occupancy sensor 6 (e.g.,button, toggle, etc.) or via a reset signal transmitted from the BMS tothe processor 12. Alternatively, the occupancy sensor 6 may beautomatically reset upon replacement of the second light 4. Furthermore,the occupancy sensor 6 may be automatically reset by turning the firstlight 2 off and a determination of a threshold ambient light leveldetected by the light sensor.

The occupancy sensor 6 may also be provided with a self-test featurewherein the occupancy sensor may periodically turn off the first light 2in order to detect proper operation of the second light 4 and/or todetect whether a fault has been corrected within a pre-determined timeperiod after a fault has been identified.

In one embodiment, the processor 12 may store measured light levelinformation in the associated memory 14 for future use. For example,measured ambient light levels may be stored over time, and trendinginformation can be generated that may be used to actively predict when asecond light 4 may fail. This may also be useful for instances in whichmultiple second lights 4 are provided for a large space, and where anunsafe condition may not result if only one of the second lights 4fails. The processor 12 may recognize the reduced ambient lighting levelcondition and transmit a signal to the BMS that an inspection iswarranted.

In some embodiments, when the occupancy sensor 6 identifies a failedsecond light 4, a visual indicator, such as but not limited to a lightemitting diode (LED), may be provided on the occupancy sensor 6 or loadcontrol device 8 to indicate failure of the second light 4. This featuremay allow for walk-through identification of a lighting failurecondition in a particular space. In addition, the occupancy sensor 6 maybe coupled to a private or public network to facilitate remotenotification when a failure of the second light occurs. In someembodiments, information of a lighting failure condition may be sent viathe Internet to a web page to enable remote monitoring of spaces. Abuilding manager or other authorized individual or agency may monitorthis information to determine if lighting replacement is required. Insome embodiments the remote notification may be sent in an e-mail or atext message to one or more mobile or desktop computers.

The occupancy sensor 6 may include any of a variety of sensortechnologies, such as passive infrared sensors (PIR), ultrasonic sensors(US), dual infrared-ultrasonic sensors, and the like.

Any of the above described embodiments may be implemented using aprocessor associated with the occupancy sensor 6. By implementing thearrangement of the system using software associated with the processor,changes to device wiring may be avoided. Alternatively, the arrangementof the system may be implemented using a combination of hardware andsoftware.

In some embodiments, the disclosed arrangement may be of advantage ifthe occupancy sensor 6 fails or if the sensing device within theoccupancy sensor fails. For embodiments in which the processor 12 isseparate from the occupancy sensor 6, the light sensor 24 may detectinstances in which the second light 4 has failed, and the processor maythen command the first light 2 to be turned on so that the monitoredarea is illuminated for occupants. For embodiments in which the lightsensor 24 is incorporated into the occupancy sensor 6, and the occupancysensing device fails, the light sensor 24 can still detect the loss ofthe second light 4 so that the light first light may be turned on.

An advantage of the disclosed arrangement is that it may be implementedwithout additional hardware. Thus, in some embodiments it may beimplemented through a change to the occupancy sensor's operatingsoftware. The disclosed system and method may be implemented in anysystem that uses an occupancy sensor for control.

Although the illustrated occupancy sensor 6 is disclosed as including adiscrete controller 12, it will be appreciated by one of ordinary skillthat the appropriate logic for implementing the disclosed features ofthis sensor may also be embodied in appropriate hardwired circuitryassociated with the occupancy sensor 6. Thus, the logic associated withthis embodiment can be in hardware, software, or a combination of thetwo. It will further be appreciated that the occupancy sensor 6 may alsoinclude any or all of the features of the embodiments described inrelation to FIGS. 3-14.

Referring now to FIG. 3, a system 50 is disclosed for implementing adaylighting scheme using an occupancy sensor 52 with a photocell orintegrated light sensor 54. The light sensor 54 may detect ambient lightlevels in the monitored space so that a base level of illumination maybe maintained in a space. The occupancy sensor 52 normally is configuredto transmit a signal to energize an associated load 56 (e.g., spacelighting) when the space is occupied, and to transmit a signal to shutoff the load 56 when the space is unoccupied after a pre-determinedtime. The system 50 may include an automated control that either turnsoff or dims the load 56 in response to an amount of available daylightin the space, as measured by the light sensor 54. Thus, in someembodiments, the occupancy sensor 52 may include an ambient lighthold-off, which allows some or all of the lights in a space to remainoff when natural lighting reaches a particular level as measured by thelight sensor 54, regardless of occupancy status of the space. Theresulting system can be effective at reducing electrical consumption.

It will be appreciated that it is desirable that the ambient lightholdoff feature only be tripped when ambient light to the space exceedsa particular threshold level. However, in some cases, the placement oflight sensor 54 configured for open-loop operation may still receivelight contributions from the load 56. For dimmed daylighting systems,this may not present a problem since the intensity of the load 56 isoften changed slowly, in near imperceptible increments. When daylightingis accomplished with switched loads though, there may be obvious changesto the light intensity when the switching occurs. For this reason, loadswitching may be performed at a time when it is not particularlynoticeable and more importantly in a way that keeps the load 56 fromswitching on and off after short periods of time.

In the disclosed system and method, the occupancy sensor's processor 58calculates a hysteresis for switching lights on and off when used inopen-loop daylighting where light contribution from the load 56 is afactor in the light sensor's measurement. In some embodiments, softwaretimeouts can be used to delay the change in state of the load 56 to keepswitching to a minimum when outside (natural) light is fluctuating nearthe trip point. In addition, a software hysteresis may be employed tofurther decrease unwanted repetitive state changes.

If the installation of the light sensor 54 used in open-loop daylightingis positioned such that some illumination from the load 56 iscontributing to the light sensor's measurement, the hysteresis may notbe large enough, which may result in the lights turning on and off atwhatever timer delays are in place.

To alleviate this problem without installer intervention, the processor58 may be programmed to perform a calibration routine whenever themanual set point for the light sensor 54 is being programmed. Thiscalibration routine may include turning the load 56 on and off severaltimes to measure the change in the amount of light that the light sensor54 measures. This change represents the amount of light that iscontributed by the load 56. The hysteresis may be automatically ormanually adjusted to be an amount greater than that change in the amountof light.

In one non-limiting example, if the light sensor 54 reads a value of “5”with the load 56 turned ON, and a value of “4.5” with the load 56 turnedOFF, the processor 58 may determine that there is a 0.5 value drop whenthe load 56 is turned off, and a 0.5 value increase when the load 56 isturned on. The hysteresis value would then be some value greater than“0.5”. For example, the hysteresis value may be twice the differencebetween the ON and OFF values. The system set point may then be setappropriately. In one embodiment, this hysteresis value may be stored innon-volatile memory 60 associated with the processor 58.

It will be appreciated that the system described above can beimplemented using an occupancy sensor having an integral light sensor,or for a system in which the occupancy sensor and the light sensor areprovided as discrete system components. In addition, the light sensormay include its own processor (not shown), in which some or all of thefunctionality described in relation to the occupancy sensor processormay be embodied in the light sensor processor. Further, such logic andcontrol may be incorporated into a load control device 60 associatedwith the occupancy sensor and light sensor.

In addition, although the illustrated occupancy sensor 52 includes adiscrete processor 58, it will be appreciated that the appropriate logicfor implementing the disclosed features of this embodiment may also beincorporated in appropriate hardwired circuitry associated with theoccupancy sensor 52, light sensor 54 and/or load control device 60.Thus, the logic associated with this embodiment can be in hardware,software, or a combination of the two. It will further be appreciatedthat the occupancy sensor 52 may also include any or all of the featuresof the embodiments described in relation to FIGS. 1, 2 and 4-14.

FIG. 4 shows a further embodiment of a wireless occupancy sensor 100that may include wireless technology to enable the sensor to be remotelyconfigured by a user. The disclosed arrangement provides an advantageover current occupancy sensors which require adjustments to be mademanually at the device using buttons, dip-switches, etc. It will beappreciated that in applications where the detectors are positioned atelevated locations (ceilings, high wall positions, etc.) the disclosedwireless occupancy sensor 100 eliminates the need for a user to climb aladder to make adjustments to the detector. In addition, a plurality ofwireless occupancy sensors can be quickly configured by a user with anappropriate remote device.

In the illustrated embodiment, the wireless occupancy sensor 100receives power from a building power source 102 and controls at leastone load 104 in response to a sensed occupancy condition in a monitoredspace. The wireless occupancy sensor 100 may additionally receivewireless signals 106 from a remote device 108 to perform one or moreinternal configuration functions. For example, a user can employ theremote device 108 to set one or more configuration and/or operationalparameters of the occupancy sensor, as will be described in greaterdetail below. In the illustrated embodiment, the remote device 108 maycall a web page 110 that includes an appropriate interface for enablinga user to remotely configure the wireless occupancy sensor 100 in adesired manner.

Referring to FIG. 5, the wireless occupancy sensor 100 may be associatedwith a load control device 112 and a load 104, such as, but not limitedto, a light. The load control device 112 may be powered via line powerfrom a building power source 102, and may provide power to the wirelessoccupancy sensor 100 via power line 114. The occupancy sensor may, inturn, provide occupancy signals to the load control device via signallines 116. In turn, the load control device 112 may selectively energizethe load 104 via power lines 118 upon receiving an “occupied” signalfrom the wireless occupancy sensor 100 along the signal lines 116.Although the wireless occupancy sensor 100 and load control device 112are illustrated as being separated devices, it will be appreciated thatthe load control functionality can also be combined into the occupancysensor.

The wireless occupancy sensor 100 may further include a processor 120for controlling one or more configuration and/or operational aspects ofthe sensor and for commanding and decoding communication signals sentbetween the occupancy sensor and the load control device 112, and/orbetween the occupancy sensor and the remote device 108. In addition, theprocessor 120 may have local memory 122 associated therewith for storinginformation including, but not limited to, configuration and operationalinformation transmitted from the remote device 108. The memory 122 maybe any of a variety of volatile or non-volatile memory devices.

The wireless occupancy sensor 100 may further include a wirelesstransceiver 124 for receiving wireless signals from the remote device108 and/or the load control device 112. The wireless transceiver 124 maybe coupled to the processor 120 to enable the processor to use theinformation received from the remote device 108 via wireless signals 106to adjust one or more configuration parameters of the occupancy sensor100.

In some embodiments, the processor 120 can command the wirelesstransceiver 124 to transmit signals back to the remote device 108 orother device to provide operational and/or configuration informationrelating to the sensor 100. In one exemplary non-limiting embodiment,the transceiver 124 may provide an acknowledgement signal to the remotedevice 108 once a configuration step is completed. It will beappreciated that although the wireless transceiver is illustrated as asingle element (i.e., chip), the wireless receiver and transmitterfunctionality may be provided as separate devices within the occupancysensor 100.

In some embodiments, the wireless occupancy sensor 100 is hard wired tothe other components of the system (power, load control device, load,etc.) to provide powering and signaling of an occupancy condition. Inother embodiments, however, the wireless transceiver 124 may becompletely wireless and may facilitate wireless occupancy signaling to awireless load control device or other control device. In suchembodiments, a separate power source, such as but not limited to, one ormore batteries, PV cells, etc., may be used as a primary or back-upsource of power to operate the occupancy sensor's circuitry.

As previously noted, a user can communicate with the wireless occupancysensor 100 remotely using a device, such as but not limited to, a mobiledevice, tablet device, or desktop device, that has an internet browser.The user may connect to a particular wireless occupancy sensor 100 bytyping in the sensor's IP address, and can configure the sensor remotelyvia the wireless transceiver 124 and processor 120. The wirelessoccupancy sensor 100 may also facilitate advanced features such as butnot limited to, scheduling, zone control and dimming.

It will be appreciated that the system may include a plurality ofoccupancy sensors. For systems in which a plurality of wirelessoccupancy sensors 100 are provided, the individual sensors may be ableto communicate with each other. For example, one sensor 100 may becoupled to a load control device (either internally or externally) sothat it can operate to turn on/off a connected load based on its ownoccupancy signal or an occupancy signal received wirelessly from anotherwireless occupancy sensor 100. For applications having multiple wirelessoccupancy sensors 100, building management personnel may connect to eachsensor remotely and set their schedules using a wireless router.

In further embodiments, the wireless occupancy sensor 100 may be able tocommunicate with other types of wireless devices such as, but notlimited to, a wireless wall switch. In such cases, the wireless wallswitch may be configured to override the occupancy sensor when theswitch is turned on, and/or reset the wireless occupancy sensor 100 tonormal operations when the switch is turned off.

In other embodiments, the wireless occupancy sensor 100 may serve as awireless access point (e.g., a Wi-Fi hotspot), enabling router-lessconnection to the occupancy sensor. Such an arrangement may enable anydevice having Wi-Fi capability to wirelessly connect to the sensor. Inone exemplary embodiment, the occupancy sensor 100 having suchfunctionality could be controlled via a custom application (“App) orother software program residing on a mobile device. Alternatively, a webpage based interface tool may be used, eliminating the need for an “App”or other software to be separately loaded, thus resulting in a platformindependent configuration.

In one non-limiting exemplary embodiment, the user may review a list ofavailable Wi-Fi networks on the remote device 106. The name of thewireless occupancy sensor 100 may appear in a screen list of availableWi-Fi options. To interface with a particular occupancy sensor, the usermay simply select that sensor from the displayed list, and by entering apassword may be connected to the individual occupancy sensor 100.Various configuration options may then be selected and adjusted asdesired. In an alternative embodiment the user may open an internetbrowser on the remote device, whereupon the user will be able to accessa web page associated with one or more occupancy sensors. The web pagemay be a homepage including a plurality of individual pages associatedwith individual occupancy sensors. The user may connect to theindividual occupancy sensors via their associated individual web page.Alternatively, and as previously noted, the user may access anindividual occupancy sensor by entering the particular sensor's IPaddress.

In some embodiments the disclosed sensor 100 may include a “locate”function, so that, once connected to the remote device 106, the devicecan be used to physically identify which occupancy sensor 100 it isconfiguring. The remote device 106 may include a softkey or other inputarrangement that causes a signal to be sent to the occupancy sensor 100,in response to which the sensor emits a visual or audible indication. Insome embodiments the indication may be a light (e.g., LED) or an audiblesound (e.g., beep).

In a further alternative embodiment, a router may provided forconnection to a group of occupancy sensors 100. With such anarrangement, the user can employ the remote device 106 to select therouter from a list of available Wi-Fi networks. Thereafter, individualsensors associated with the router can be selected and configured usingthe remote device.

It will be appreciated that an advantage of the disclosed arrangement ascompared to prior systems and devices is that a user can connect to oneor more occupancy sensors directly, without requiring a separate networkor an Internet connection (i.e., an access point connection). Thus, insome embodiments the remote device connects to a router, and the routerprovides access to the individual occupancy sensors (i.e., a clientconnection). In addition, the disclosed arrangement enables a user to goback and forth between a client connection arrangement and an accessconnection arrangement, which can be user set.

An exemplary remote configuration embodiment will now be described inrelation to FIGS. 6A-6D. In an embodiment, the wireless transceiver 124is a Wi-Fi transceiver capable of operating in a micro-Access Point(μAP) mode. The transceiver 124 may serve web pages to connectedclients. As previously noted, a variety of sensorconfigurations/properties can be modifiable from the served web pages. Anon-exclusive and non-limiting listing of such configurations/propertiesinclude setting a delay time for unoccupied mode, adjusting the sensorfield of view, enabling/disabling test mode, enabling/disabling autoadapting functionality, enabling/disabling forced on/forced off mode,setting the sensor in different modes such as “auto on/off” or “manualon/off”, setting up daylighting functionality, calibrating an associatedphotocell using auto or manual calibration, enabling/disabling a walkthrough mode, enabling/disabling dimming using pre-set light levels,adjusting sensor sensitivity, and the like. In some embodiments, theserved web pages may enable the user to upgrade sensor and/or Wi-Fitransceiver firmware.

In some embodiments, the wireless network associated with the wirelessoccupancy sensor 100 may be secured with a user selectable password orpassphrase. The status of one or more connected sensors 100 may beviewed by all connected users on their associated remote device. Inaddition, configuration settings may require an additionaladministrative password to be employed.

In an exemplary embodiment, commissioning of a wireless occupancy sensor100 may be performed via a remote user device 108, such as but notlimited to a laptop, PC, smartphone, or tablet loaded with anappropriate web-browser. The occupancy sensor 102 may include a Wi-Fiaccess point using b/g/n standards and Wi-Fi Protected Access (WPA)encryption. A service set identification (SSID) may be broadcast bydefault, where the SSID may include a device ID portion and a mediaaccess control (MAC) address portion.

Hosted web pages may be size-appropriate for viewing the web page in amobile browser (when the device is a smart phone or other small formfactor device). FIG. 6A shows an exemplary “General Status” page 126,which may include information regarding the connected occupancy sensor100, such as the device type 128, the device status 130, the occupancystatus 132, the light level 134, the device status 136 and the MACaddress 138. A “User Options” tab 140 and an “Administrator Options” tab142 may also be included. A “Locate Device” soft key 144 may also beincluded, selection of which may cause the connected sensor 100 to emitan audible or visual alert to show its physical location, as previouslydescribed.

Although not shown, the remote device may display data that isrepresentative of the operation of the occupancy sensor during aprevious time period. Such information may be used to diagnose problemswith the sensor (e.g., where the sensor has been turning the load on atan inordinate rate), or it may be used to determine occupancy rates fora monitored space (e.g., telling the user how many times an individualhas entered the space on a given day).

FIG. 6B shows an exemplary “User Options” page 146, which may beaccessible by selecting the “User Options” tab 140 in the screen shownin FIG. 6A. This page may include a pair of soft keys 148, 150 enablingone or more connected loads 104 (i.e., lights) to be turned on or off. Adimming bar 152 may enable selective dimming of the associated load 104.A pair of preset softkeys 154, 156 are also be provided to enable theuser to reset the occupancy sensor 100 to factory default settings,and/or to enable implementation of user preset settings.

FIG. 6C shows an exemplary “Admin Options” page 158, which may beaccessible by selecting the “Admin Options” tab in the screen shown inFIG. 6A. This page may include an “Occupancy Sensor” soft key 160operable for adjusting sensor settings that are typically controlled viamanual inputs, such as trim pots, dip switches, and the like. Devicepresets may be configured and factory defaults may be restored onsubsequent pages. A “Photocell Options” soft key 162 enables a user toadjust photocell configuration settings; and, a “Network” soft key 164enables adjustment network settings, such as but not limited to,changing various passwords, changing an SSID, changing a Wi-Fiencryption password, adjusting radio power range (e.g., low, medium,high), displaying available networks, setting load control deviceoptions, setting wall switch options, setting scheduler options, and thelike. FIG. 6D shows an example of an “Occupancy Sensor Configuration”page 166, which may include a “Tech Mode” soft key 168 for enabling aninstaller to check range, sensitivity, or other features of the sensor.A “Sensor Mode” soft key 170 is also shown for enablingactivation/deactivation of one or more PIR, US, IR or other sensorelements of the occupancy sensor. An “Auto Adapting” soft key 172 mayenable a user to enable/disable an auto adapting feature in which timedelay and sensitivity settings are continually adjusted to occupantpatterns of use. A “Walkthrough” soft key 174 may enable/disable awalkthrough mode of the occupancy sensor. Walkthrough mode may enablethe sensor to turn the lights off shortly after the person leaves theroom, and is useful when a room is typically only momentarily occupied.A “Test Mode” soft key 176 may enable the user to set a delayed-off timefor an associated load to enable the user to perform a walk test of themonitored area. “Cancel” and “Save” soft keys 178, 180 are also providedto enable the user to cancel or save the selections made on the page166.

FIG. 7 shows an exemplary embodiment in which the remote device 108 mayinclude a Wi-Fi enabled laptop, PC, smart phone tablet, or the likerunning a standard web-browser. A wireless router 182 may providewireless connectivity for the laptop, PC, smartphone tablet, etc. toenable connection to the Internet 184 via an appropriate modem 186. Inone embodiment, an application running on the remote device 108 may beconfigured to query one or more of the wireless occupancy sensors 100 onthe Wi-Fi network 188. The remote device 108 may then configure one orall of the wireless occupancy sensors 100, which are coupled to one ormore loads 104, on the Wi-Fi network 188. Control of selected individualwireless occupancy sensors 100 may also be performed, includingpush/pull of settings to/from one or more sensors.

FIGS. 8A-8D show a plurality of screens on an exemplary smart phoneillustrating exemplary provisioning steps for linking a remote device108 to the Wi-Fi network 188 of FIG. 7. In FIG. 8A, the user is promptedto search for available Wi-Fi networks. In FIG. 8B, the network scanresults return three different available networks. In FIG. 8C, the userselects network GMX (Wi-Fi network 188), and is prompted to enter anappropriate passphrase. In FIG. 8D the user is shown a messageindicating that provisioning was successful.

The wireless transceiver 124 may use any of a variety of suitablewireless transmission technologies including infrared transmission usinga standard from the Infrared Data Association (IrDA), RF transmissionusing one of the many standards developed by the Institute of Electricaland Electronic Engineers (IEEE), or any other standardized and/orproprietary wireless communication technology. In one non-limitingexemplary embodiment, the wireless transceiver 124 uses Wi-Fitechnology.

The disclosed wireless occupancy sensor 100 may include any of a varietyof sensor technologies, such as, but not limited to, passive infraredsensors, ultrasonic sensors, dual infrared-ultrasonic sensors, and thelike. Further, the load 104 can be any of a variety of electrical loads,such as, but not limited to, lighting, heating, ventilation and thelike.

Although the illustrated wireless occupancy sensor 100 includes adiscrete processor 120, it will be appreciated that the appropriatelogic for implementing the disclosed features of this sensor may also beembodied in appropriate hardwired circuitry associated with theoccupancy sensor 100. Thus, the logic associated with this embodimentcan be in hardware, software, or a combination of the two. It willfurther be appreciated that the occupancy sensor 100 may also includeany or all of the features of the embodiments described in relation toFIGS. 1-3 and 9-14.

It will be appreciated that one or more of the features disclosed inrelation to FIGS. 4-8D are not limited to occupancy sensors. Thus, anyor all of the Wi-Fi features described in relation to FIGS. 4-8D couldalternatively be implemented in a load control device (i.e., apowerpack), a photocell or any other lighting control device.

Low voltage occupancy sensors are sensors without a relay, and as suchthey cannot directly control a connected load. In order to control aconnected load, low voltage occupancy sensors must be connected to aload control device (i.e., a power pack) having a relay. Thus, forapplications that require multiple occupancy sensors (e.g., large halls,multiple entrance rooms, or stairways), a plurality of low voltageoccupancy sensors are often used in combination with a separate loadcontrol device. Low voltage occupancy sensors require little power tooperate, and the load control device switches the load on/off inresponse to a signal from the occupancy sensors.

Line voltage sensors commonly include sensors and relays; and, linevoltage sensors are typically used for single-room single-sensorapplications. In addition, current line voltage occupancy sensors do notprovide a low voltage output and an interface for low voltage sensors.

Referring to FIGS. 9-11, a line voltage occupancy sensor 200 isdisclosed including at least one load control device 202 and at leastone relay 204. As will be described, the disclosed line voltageoccupancy sensor 200 can be used to power one or more low voltageoccupancy sensors 206 without the need for a separate load controldevice. That is, the line voltage occupancy sensor 200 can act as a loadcontrol device for the associated low voltage occupancy sensors 206 a-b.

As shown in FIG. 9, the line voltage occupancy sensor 200 is connectedto a building main power supply 208. The line voltage occupancy sensor200 receives the line voltage from the building main power supply 208,and transforms the line voltage in order to power a plurality of lowvoltage occupancy sensors 206 a-b. The line voltage occupancy sensor 200may also provide power directly to one or more connected loads 210 a-d.FIG. 9 shows two low voltage occupancy sensors 206 a-b and four loads210 a-d, but it will be appreciated that any number of low voltageoccupancy sensors and/or loads may be used.

In one embodiment, shown in FIG. 10, the disclosed line voltageoccupancy sensor 200 may include an occupancy sensor element 212 and aphotocell 214. The sensor 200 receives power from a main power supply208 and converts it to low voltage DC power using an AC/DC converter 216and isolation transformer 218. A low voltage power supply 220 having alow voltage output interface 222 is employed to provide power to one ormore low voltage occupancy sensors 206 via DC power wires 223.

To receive operational signals from the connected low voltage occupancysensors 206, the line voltage occupancy sensor 200 may also include atleast one input interface 224 that is configured to couple with one ormore analog or digital communication wires 225 (FIG. 9). The inputinterface 224 is coupled to an analog/digital (A/D) communicationinterface 226 so that analog signals from the low voltage sensors (viacommunications lines 225) may be converted to digital signal as requiredbefore being transmitted to the sensor's processor 228. Thus arranged,the processor 228 may command the sensor relay 204 to provide power toone or more connected loads 210 a-d based on signals received from thelow voltage occupancy sensors 206 a-b.

The line voltage sensor 200 may also include components and circuitryfor providing dimming of the connected loads 210 a-d. In one embodiment,a power supply 226 may be coupled between the isolation transformer 218and 0-10 Volt circuitry 229. The 0-10 Volt circuitry 229 may be alsocoupled to the processor 228. Based on the signals received from one ormore of the low voltage occupancy sensors 206 a-b, the processor maycontrol the 0-10V circuitry 229 to provide less than full power to theconnected loads 210 a-d. In this manner, the connected loads can bedimmed. In one embodiment the line voltage sensor 200 can include anappropriate dimming circuitry to facilitate dimming of one or moreconnected low voltage sensors 206. Alternatively, or in addition, theline voltage sensor 200 can include a power supply that powers the lowvoltage sensors 206.

As shown in FIG. 11, the line voltage occupancy sensor 200 can also beused to power a low voltage photo cell 230 and/or a low voltage switchstation 232 via power lines 223. In addition, the line voltage occupancysensor 200 can receive analog or digital signals from these componentsas well as from the low voltage occupancy sensor 206 via communicationlines 225. Separate dimming wiring 227 may also be included between theline voltage occupancy sensor 200 and the connected loads 210 a-d forproviding the aforementioned dimming functionality.

Although the illustrated embodiment shows a line voltage occupancysensor 200 having a single relay, load control elements, and interfaces,it will be appreciated that the sensor 200 can be provided with multiplerelays, multiple sets of load control elements, and multiple interfacesto enable the sensor 200 to act as a load control device for a largenumber of low voltage occupancy sensors and/or other low voltagedevices.

As will be appreciated, the disclosed line voltage occupancy sensor 200may have expanded uses as compared to conventional line voltage sensors,enabling it to be extended to large area applications. By integrating alow voltage power supply (i.e., a power pack), the disclosed sensor 200can supply power to a plurality of low voltage occupancy sensors thatcan be positioned at various locations within a large space. Byincluding an interface to receive an output from each of the low voltageoccupancy sensors, the disclosed sensor 200 can receive signals from theone or more of the low voltage occupancy sensors and can control theassociated load(s) in response thereto. Thus, the disclosed arrangementoffers a simplified and lower cost solution as compared to currentarrangements, as the need for a separate power pack is eliminated, andthe line voltage occupancy sensor takes its place.

As will be appreciated, the disclosed sensor 200 can be used to power(and to receive operational signals from) greater or fewer numbers oflow voltage occupancy sensors, photocells, and wall switches as areshown in FIGS. 9-11. In addition, other low voltage devices in additionto low voltage occupancy sensors, photocells and wall switches may alsobe powered using the disclosed sensor 200. Although the illustratedoccupancy sensor 200 includes a discrete processor 228, it will beappreciated that the appropriate logic for implementing the disclosedfeatures of this sensor may also be embodied in appropriate hardwiredcircuitry associated with the occupancy sensing element 212. Thus, thelogic associated with this embodiment can be in hardware, software, or acombination of the two. It will further be appreciated that theoccupancy sensor 200 may also include any or all of the features of theembodiments described in relation to FIGS. 1-8 and 12-14.

Referring to FIG. 12, an occupancy sensor 300 is includes an integralemergency interface 302 to a control system 304 that is capable ofoverriding the sensor's normal functionality under emergency conditions.In one embodiment, the control system 304 is a building automationsystem or building management system (hereafter “BMS”). The BMS is usedto provide real time management of, and access to, systems such aslighting, HVAC, fire, security and the like. Under emergency conditions,such as (but not limited to) when a fire condition is detected in abuilding, it is desirable to enable the BMS to override the normaloperation of the occupancy sensors positioned throughout the building toensure that the lights are on to aid emergency personnel, such asfiremen as well as security personnel.

The emergency interface 302 is integral to the occupancy sensor 300, andenables the BMS 304 to energize a load associated with the sensor andthe load control device 308. In the illustrated embodiment, theemergency interface 302 couples the BMS 304 to the sensor's processor306, though this is not critical, and in some embodiments, the interface302 may enable the BMS 304 to communicate directly with the load controldevice 308 via communication link 310. As arranged, under emergencyconditions the BMS 304 can operate to force the occupancy sensor toenergize the load(s) associated with the load control device 308, thusensuring that the associated load remains powered, regardless of theoccupancy status of the monitored space.

As will be appreciated, providing an integral emergency interface 302 inthe occupancy sensor 300 eliminates the need for an external interfaceto ensure that the BMS can control all of the lighting in a buildingunder emergency conditions. This is an advantage over current occupancysensors which require a separate external interface component in orderto couple to the BMS 304.

Although the illustrated occupancy sensor 300 includes a discreteprocessor 306, it will be appreciated that the appropriate logic forimplementing the disclosed features of this sensor may also be embodiedin appropriate hardwired circuitry associated with the occupancy sensingelement 312. Thus, the logic associated with this embodiment can be inhardware, software, or a combination of the two. It will further beappreciated that the occupancy sensor 300 may also include any or all ofthe features of the embodiments described in relation to FIGS. 1-11, 13and 14.

Referring to FIG. 13, an occupancy sensor 400 is disclosed that activelyadjusts an occupant sensing threshold to account for changes in ambienttemperatures in a monitored space. Passive infrared (PIR) occupancysensors operate by sensing a body having a heat signature in excess ofbackground infrared (IR) levels. That is, PIR sensors observe adifference in temperature between the body and the background and theyregister that as a change. Depending on the magnitude of this change,logic built into the PIR occupancy sensor either ignores the change ifit is below a certain threshold, or causes an “occupied” signal to beissued if the change is above the threshold required to signify anoccupied condition. As the ambient temperature of a monitored spacerises, the difference between human body temperature and the ambienttemperature decreases, and as a result PIR occupancy sensors can be lessable to differentiate the heat of a human body from the heat of thesurroundings. This may be particularly acute where the occupancy sensoris deployed in a hot climate where the temperature of the monitoredspace can be very high if air conditioning is not in use.

The disclosed occupancy sensor 400 thus may include a passive infrared(PIR) sensing element 402 and a temperature sensing element 404 coupledto a processor 406. Based on the received temperature information fromthe temperature sensing element 404, the processor 406 can adjust asensing threshold required to transmit an “occupied” signal along awired or wireless communications channel 408 to a load control device410 associated with the monitored space.

In one non-limiting exemplary embodiment, the processor 406 usesinformation from the temperature sensing element 404 to adjust a sensingthreshold so that a greater or lesser temperature differential betweenthe monitored space and a sensed body must be exceeded before anoccupied condition is signaled and an associated load is energized. Inone embodiment, as the temperature of the monitored space increases (assensed by the temperature sensing element 404), the processor 406decreases the temperature differential required to signal an occupiedcondition.

In one non-limiting exemplary embodiment, the processor 406 employs analgorithm to adjust this threshold. In other embodiments, adjustmentvalues are provided in a lookup table in non-volatile memory 412associated with the processor 406. Adjustment values could be stored ina look up table associated with the processor 406. In yet anotherembodiment, the threshold adjustment may be manually entered via a userinput device 414 such as a dip switch, trim pot, rotary switch, or thelike.

Although the illustrated embodiment shows the temperature sensingelement 404 as being internal to the occupancy sensor 400, it will beappreciated that the temperature sensing element could alternatively bean external device. Such an arrangement may be appropriate when using ananalog PIR sensing element 402. In such cases, the temperature sensingelement 404 may be any appropriate temperature sensing device, such as athermocouple, a resistance temperature detector (RTD), a thermistor, orthe like. When using a digital PIR sensing element 402, the digital PIRsensor itself may provide the desired temperature data for use by theprocessor 406, and thus a discrete temperature sensing element 404 maynot be required.

Although the illustrated occupancy sensor 400 includes a discreteprocessor 406, it will be appreciated that the appropriate logic forimplementing the disclosed features of this sensor may also be embodiedin appropriate hardwired circuitry associated with the PIR sensingelement 402. Thus, the logic associated with this embodiment can be inhardware, software, or a combination of the two. It will further beappreciated that the occupancy sensor 400 may also include any or all ofthe features of the embodiments described in relation to FIGS. 1-12 and14.

Referring to FIG. 14, a directional occupancy sensor 500 is disclosedhaving a plurality of sensor elements 502 a-d, each of which ispositioned at a different “corner” of the sensor 500, so that eachelement is responsible for sensing occupancy in a particular portion ofa covered space. The disclosed occupancy sensor 500 can thus discernfrom which portion of the space occupancy is sensed. Lighting controlmay be adjusted (i.e., turned on or off or dimmed) based on the portionof the space in which occupancy is sensed.

Since different sensor elements 502 a-d are employed to cover differentportions of the covered space, the coverage area of the occupancy sensor500 can be adjusted by switching on or off particular sensor elements502 a-d, eliminating the need for using masking inserts. In oneembodiment, each sensor element 502 a-d is associated with an individualchannel. The individual channels can be turned on or off via a userinput device 504 such as a dip switch, trip pot, rotary switch or thelike. This enables the user to selectively turn on/off particular sensorelements 502 a-d so that occupancy is detected in fewer than allportions of the covered spaces. Channel operation can also oralternatively be adjusted using an associated processor 506 coupled to alocal or remote controller 508 via a wired or wireless communicationschannel 510.

One or more sensor elements 502 a-d may be associated with a singlechannel, and thus one or more portions of the occupancy sensor 500 maybe turned on or off by adjusting a single channel. The disclosedarrangement is advantageous for applications in which, for example, oneof the sensor elements 502 a is positioned to “look” toward a doorway,while the remaining sensor elements 502 b-d are positioned to “look” atthe interior portions of the covered space. In such a case, the channelassociated with sensor element 502 a could be turned off so thatmovements attributable to people in a hallway adjacent to the door wouldnot be sensed. This would eliminate instances in which a person passingby the door causes the lights in the room to be turned on even though noone is present in the covered space.

In one embodiment the sensor elements are passive infrared (PIR)sensors, however, it will be appreciated that other types of sensingelements may be used such as ultrasonic, acoustic, video and the like.In addition, the occupancy sensor 500 may include combinations ofdifferent types of sensing elements. Moreover, although the illustratedembodiment shows four individual sensing elements 502 a-d, the occupancysensor 500 could include fewer or greater than four elements.

Although the illustrated occupancy sensor 500 includes a discreteprocessor 506, it will be appreciated that the appropriate logic forimplementing the disclosed features of this sensor may also be embodiedin appropriate hardwired circuitry associated with the individualsensing elements 502 a-d. Thus, the logic associated with thisembodiment can be in hardware, software, or a combination of the two. Itwill be appreciated that the occupancy sensor 500 may also include anyor all of the features of the embodiments described in relation to FIGS.1-13.

An exemplary method for controlling an electrical load will now bedescribed in relation to FIG. 15. At step 1000, a load control devicereceives a lighting signal representative of a lighting level of amonitored area. At step 1100, the load control device energizes anelectrical load when the lighting signal indicates the lighting level isbelow a predetermined threshold lighting level and an occupancy sensorassociated with the monitored area indicates the monitored area isvacant. In some embodiments, the electrical load is a first light havinga relatively high-intensity level. A second light, having a relativelylower intensity level than the intensity level of the first light, mayalso be provided, and the predetermined threshold lighting level may beassociated with a second light. At step 1200, an indication is providedto a user that the second light has failed if the lighting signalindicates the lighting level is below a predetermined threshold lightinglevel. In some embodiments the indication to a user is commanded fromthe occupancy sensor via at least one of e-mail, text message, voicemessage or web page. At step 1300, a reset function of the occupancysensor is actuatable to return the load control system to normaloperation. In one embodiment, the reset function may be actuatable byreplacing the second light.

An exemplary alternative method for controlling an electrical load willnow be described in relation to FIG. 16. At step 2000, an ambient lightlevel associated with a monitored space is detected by a light sensor.At step 2100, an amount of light contributed by the electrical load iscompensated for in determining the amount of light in the space asmeasured by the light sensor. At step 2200, this compensating mayinclude performing a calibration when a manual set point of the lightsensor is being programmed. At step 2300, the calibration may includeswitching the electrical load on and off a plurality of times to measurean amount of light level change that occurs. In further embodiments, thecalibration may include adjusting a hysteresis value to be an amountgreater than said light level change. At step 2400, an electrical loadis controlled in response to an amount of light in the space as measuredby the light sensor. In some embodiments, the electrical load iscontrolled to be in a de-energized or dimmed state when the measuredamount of light in the space exceeds a predetermined level. In otherembodiments, the electrical load is controlled to be in a dimmed orde-energized state regardless of the occupancy condition of themonitored space.

An exemplary further method for controlling a load with a wirelessoccupancy sensor will now be described in relation to FIG. 17. At step3000, wireless signals from a remote device are received at a wirelessoccupancy sensor. At step 3100, the wireless signals configure theoccupancy sensor. In some embodiments, a processor in communication witha wireless transceiver control a configuration or an operationalcharacteristic of the occupancy sensor and command and decodecommunication signals sent between the occupancy sensor and the remotedevice. At step 3200, information including the configuration or theoperational information transmitted from the remote device is stored innon-volatile memory associated with the processor. At step 3300, thewireless transceiver transmits information from the occupancy sensor tothe remote device to provide operational and/or configurationinformation relating to the sensor. At step 3400, an acknowledgementindication is provided to a user when the wireless transceiver receivesa signal from the remote device. In some embodiments, theacknowledgement indication may include an audible or visual indicationat least one of the occupancy sensor and the remote device.

Some of the inventive principles of the disclosure relate to techniquesfor occupancy sensing, in particular, for sensing the presence or motionof a person or a moving object in an area of interest. In oneembodiment, lighting levels can be adjusted in or about the area ofinterest responsive to sensing the person or moving object. In anotherembodiment, a security alarm can be triggered responsive to sensing theperson or moving object.

The disclosed system and method may provide enhanced safety foroccupancy sensing systems used to monitor spaces for which public safetyis implicated. Embodiments of the disclosed occupancy sensor can be usedwith conventional load control devices or enhanced load control devicesto provide the desired fail safe illumination of such spaces.

Some embodiments of the disclosed device may be implemented, forexample, using a storage medium, a computer-readable medium or anarticle of manufacture which may store an instruction or a set ofinstructions that, if executed by a machine (i.e., processor ormicrocontroller), may cause the machine to perform a method and/oroperations in accordance with embodiments of the disclosure. By way ofexample, such a machine may include, but not limited to, any suitableprocessing platform, computing platform, computing device, processingdevice, computing system, processing system, computer, processor, or thelike, and may be implemented using any suitable combination of hardwareand/or software. The computer-readable medium or article may include,but not limited to, any suitable type of memory unit, memory device,memory article, memory medium, storage device, storage article, storagemedium and/or storage unit, for example, memory (including, but notlimited to, non-transitory memory), removable or non-removable media,erasable or non-erasable media, writeable or re-writeable media, digitalor analog media, hard disk, floppy disk, Compact Disk Read Only Memory(CD-ROM), Compact Disk Recordable (CD-R), Compact Disk Rewriteable(CD-RW), optical disk, magnetic media, magneto-optical media, removablememory cards or disks, various types of Digital Versatile Disk (DVD), atape, a cassette, or the like. The instructions may include any suitabletype of code, such as source code, compiled code, interpreted code,executable code, static code, dynamic code, encrypted code, and thelike, implemented using any suitable high-level, low-level,object-oriented, visual, compiled and/or interpreted programminglanguage.

While certain embodiments of the disclosure have been described herein,it is not intended that the disclosure be limited thereto, as it isintended that the disclosure be as broad in scope as the art will allowand that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of particular embodiments. Those skilled in the artwill envision additional modifications, features, and advantages withinthe scope and spirit of the claims appended hereto.

What is claimed is:
 1. A load control system, comprising: an occupancysensor for sensing an occupancy condition of a monitored area; and alight sensor for providing a lighting signal representative of alighting level of the monitored area; wherein, regardless of theoccupancy condition of the monitored area, an associated load isenergized when the lighting signal indicates the lighting level is belowa predetermined threshold lighting level.
 2. The load control system ofclaim 1, wherein the associated load comprises a first light, and thesystem further comprises a second light configured to be energized whenthe occupancy condition of the monitored area is determined by theoccupancy sensor to be a vacant condition.
 3. The load control system ofclaim 2, wherein the predetermined threshold lighting level is alighting level associated with the second light.
 4. The load controlsystem of claim 2, wherein when the lighting signal indicates thelighting level is below the predetermined threshold, the system presentsan indication to a user that the second light has failed.
 5. The loadcontrol system of claim 1, further comprising a processor associatedwith the occupancy sensor, the processor for receiving the lightingsignal and for energizing the load when the lighting signal indicatesthe lighting level is below the predetermined threshold lighting level.6. The load control system of claim 1, further comprising: a wirelesstransceiver associated with the occupancy sensor, the wirelesstransceiver for receiving wireless signals from a remote device toconfigure the occupancy sensor from a remote location; wherein saidwireless transceiver is further configured to transmit wireless signalsto the remote device, said transmitted wireless signals includinginformation representative of an operational characteristic of saidoccupancy sensor during a previous time period.
 7. A method forcontrolling an electrical load, comprising: receiving, at a load controldevice, a lighting signal representative of a lighting level of amonitored area; and energizing an electrical load when the lightingsignal indicates the lighting level is below a predetermined thresholdlighting level and an occupancy sensor associated with the monitoredarea indicates the monitored area is vacant.
 8. The method of claim 7,wherein the electrical load comprises a first light, and thepredetermined threshold lighting level is associated with a second lighthaving an intensity that is less than an intensity of the first light.9. The method of claim 7, further comprising a load control device,wherein the associated load comprises a first light, and the loadcontrol device selectively energizes the first light when the occupancysensor transmits an occupancy signal indicative of an occupied conditionof the monitored space.
 10. The method of claim 7, further comprising aprocessor associated with the occupancy sensor, the processor forreceiving the lighting signal and for energizing the load when thelighting signal indicates the lighting level is below the predeterminedthreshold lighting level.
 11. The method of claim 7, further comprising:receiving, at the occupancy sensor, wireless signals from a remotedevice, said received wireless signals configuring the occupancy sensor;and transmitting, from said wireless occupancy sensor, wireless signalsto the remote device, said transmitted wireless signals includinginformation representative of an operational characteristic of saidwireless occupancy sensor during a previous time period.